Discovery of a Rare Pterosaur Bone Bed in a Cretaceous Desert with Insights on Ontogeny and Behavior of Flying Reptiles

et al. (2014) Discovery of a Rare Pterosaur Bone Bed in a Cretaceous Desert with Insights on Ontogeny and Behavior of Flying Reptiles. PLOS ONE 9(8): e100005. doi:10.1371/journal.pone.0100005 Discovery of a Rare Pterosaur Bone Bed in a Cretaceous Desert with Insights on Ontogeny and Behavior of Flying Reptiles Paulo C. Manzig 0 Alexander W. A. Kellner 0 Luiz C. Weinschu tz 0 Carlos E. Fragoso 0 Cristina S. Vega 0 Gilson B. Guimara es 0 Luiz C. Godoy 0 Antonio Liccardo 0 Joa o H. Z. Ricetti 0 Camila C. de Moura 0 Andrew A. Farke, Raymond M. Alf Museum of Paleontology, United States of America 0 1 Centro Paleontolo gico da UnC (CENPA LEO), Universidade do Contestado , Mafra, Santa Catarina , Brazil , 2 Programa de Po s-Graduac a o IEL-Labjor, Universidade Estadual de Campinas (UNICAMP) , Campinas, Sa o Paulo , Brazil , 3 Laboratory of Systematics and Taphonomy of Fossil Vertebrates, Departamento de Geologia e Paleontologia, Museu Nacional/Universidade Federal do Rio de Janeiro , Rio de Janeiro , Brazil , 4 Universidade Estadual de Ponta Grossa , Ponta Grossa, Parana , Brazil , 5 Departamento de Geologia, Universidade Federal do Parana , Curitiba, Parana , Brazil , 6 Departamento de Geociencias, Universidade Estadual de Ponta Grossa , Ponta Grossa, Parana , Brazil A pterosaur bone bed with at least 47 individuals (wing spans: 0.65-2.35 m) of a new species is reported from southern Brazil from an interdunal lake deposit of a Cretaceous desert, shedding new light on several biological aspects of those flying reptiles. The material represents a new pterosaur, Caiuajara dobruskii gen. et sp. nov., that is the southermost occurrence of the edentulous clade Tapejaridae (Tapejarinae, Pterodactyloidea) recovered so far. Caiuajara dobruskii differs from all other members of this clade in several cranial features, including the presence of a ventral sagittal bony expansion projected inside the nasoantorbital fenestra, which is formed by the premaxillae; and features of the lower jaw, like a marked rounded depression in the occlusal concavity of the dentary. Ontogenetic variation of Caiuajara dobruskii is mainly reflected in the size and inclination of the premaxillary crest, changing from small and inclined (,115u) in juveniles to large and steep (,90u) in adults. No particular ontogenetic features are observed in postcranial elements. The available information suggests that this species was gregarious, living in colonies, and most likely precocial, being able to fly at a very young age, which might have been a general trend for at least derived pterosaurs. - Funding: AWAK acknowledges funding from the Fundacao Carlos Chagas Filho de Amparo a` pesquisa do Rio de Janeiro (FAPERJ # E-26/102.737/2012) and the Conselho Nacional de Desenvolvimento Cientfico e Tecnolo gico (CNPq # 307276/2009-9). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. Pterosaurs comprise an extinct group of flying reptiles that have been recovered on all continents [1]. Notwithstanding their distribution, their record is rather patchy, with most occurrences limited to fragmentary remains that in several cases were only briefly reported in the literature [2]. Most pterosaurs are known from ancient coastal or shallow marine deposits and the number of species that lived deep inside the continents is limited [3,4], particularly from desert environments [5]. Most species are based on one incomplete individual, and aside from one potential exception of a collection of flattened specimens [6], no pterosaur accumulation can be regarded as a bone bed preserving several individuals that can confidently be assigned to the same species and at least potentially be regarded as representing the same or successive populations [7]. This has hampered the discussion of several biological questions regarding those animals, such as ontogenetic growth, development of cranial crests, and behavior. Here we describe a rare pterosaur bone bed composed of hundreds of bones from the outskirts of Cruzeiro do Oeste, southern Brazil. The deposits correspond to the Caiua Group [8] that represents a sand sea formed in an interior paleodesert whose paleontological content was up to know limited to infrequent tetrapod ichnofossils [9,10] (Figure 1). This exceptional occurrence, combined with the large number of three-dimensionally preserved individuals, sheds new light on the biology of those rather enigmatic volant animals. Materials and Methods Phylogenetic Analysis In order to determine the phylogenetic position of Caiuajara dobruskii gen. et sp. nov., we performed a phylogenetic analysis using PAUP 4.0b10 for Microsoft Windows [11] using the TBR heuristic searches performed using maximum parsimony. Characters were given equal weight and treated as unordered (ACCTRAN setting). This analysis is based on previous cladistic studies (List S3 in File S1). Nomenclatural Acts The electronic edition of this article conforms to the requirements of the amended International Code of Zoological Figure 1. Localization and stratigraphic framework of the new pterosaur locality. (A) Map of South America and the geographic position of Cruzeiro do Oeste. (B) Stratigraphic chart showing the relation between the distinct stratigraphic units of the Bauru Basin [10]. (C) Detailed stratigraphic section of the quarried beds of the Goio-Ere Formation, showing the location where the fossils were recovered. doi:10.1371/journal.pone.0100005.g001 Figure 2. Holotype (CP.V 1449 left) and one paratype (CP.V 2003, right) of Caiuajara dobruskii gen. et sp. nov. separated by a red line, showing skull and postcranial elements. Scale bar equals 100 mm. Abbreviations: cor, coracoid; cv, cervical vertebra; d, dentary; dca, distal carpal series; dcr, dentary crest; f, frontal; hu, humerus; hy, hyoid bone; l, left; man, mandible; mcfo, meckelian fossa; mcI-III, metacarpal IIII; mcIV, metacarpal IV; oc, occipital condyle; p, parietal; pmcr, premaxillary crest; ph1d4, first phalanx of manual digit IV; ph2d4, second phalanx of manual digit IV; ph4d4, forth phalanx of manual digit IV; pof, postfrontal; ptd, pteroid; q, quadrate; r, right; ra, radius; ri, rib; un, ungueal. doi:10.1371/journal.pone.0100005.g002 Figure 3. Skull of Caiuajara dobruskii gen. et sp. nov. (holotype, CP.V 1449) with the shape of an adult individual. Scale bar equals 50 mm. Abbreviations: d, dentary; dcr, dentary crest; dep, depression; exp, ventral expansion of the premaxilla; f, frontal; fcr, frontal crest; fo, foraminae; m, maxilla; oc, occipital condyle; op, opisthotic; p, parietal; pm, premaxilla; pmcr, premaxillary crest; q, quadrate; soc, supraoccipital. The quadrate is inverted. doi:10.1371/journal.pone.0100005.g003 Nomenclature, and hence the new names contained herein are available under the Code from the electronic edition of th (...truncated)